A new principle in design of composite materials: Reinforcement by interlocked elements

We propose a new materials design concept based on the use of regular assemblies of topologically interlocked elements. A particular implementation of this concept, viz. a layer of tetrahedron-shaped elements, was studied in some detail. The packing arrangement in the layer is such that each individual element is held in place by its immediate neighbours. This structure can provide a load-bearing skeleton of a composite material. A second phase, serving as a matrix or binder, can be selected to provide special structural or functional properties such as thermal or sound insulation, fluid transport, controlled electrical conductivity, etc. It is envisaged that strong and flexible composite materials with high impact resistance can be created on this basis. A model specimen assembled according to this topological principle was tested with respect to its stiffness and load bearing capacity. First experimental and theoretical results show that a layer consisting of many interlocked elements has a much larger mechanical compliance than its monolithic counterpart, and can withstand considerable deformations. Other possible shapes of three-dimensional elements interlocked into a monolayer and the principles of their generation are discussed. The design principle proposed opens up new avenues for creating multifunctional composite materials. Crown